When the sociologist Diane Vaughan came up with the term “the normalization of deviance,” she was referring to nasa administrators’ disregard of the flaw that caused the Challenger space shuttle to explode, in 1986. The idea was that people in an organization can become so accepting of a problem that they no longer consider it to be problematic. (In the case of the Challenger, nasa had been warned that the shuttle’s O-rings were likely to fail in cold temperatures.) Consider Facebook: for years, its leadership has known that the social network has abetted political polarization, social unrest, and even ethnic cleansing. More recently, it has been aware that its algorithms have promoted misinformation and disinformation campaigns about covid-19 and vaccines. Over the past year, the company made piecemeal attempts to remove false information about the pandemic, issuing its most comprehensive ban in February. An analysis last month by the nonprofit group First Draft, however, found that at least thirty-two hundred posts making unfounded claims about covid-19 vaccines had been posted after the February ban. Two weeks ago, the top post on Facebook about the vaccines was of Tucker Carlson, on Fox News, “explaining” that they don’t work.